Plunger actuated electrical switches



April 4, 1967 c. E. JUGGINS 3,312,804

PLUNGER ACTUATED ELECTRICAL SWITCHES Filed Feb. 1. 1965 INVENTOR CYRIL ERNEST JUGGINS HIS ATTORNE Y United States Patent ()fiice 3,312,804 Patented Apr. 4, 1967 Claims This invention relates to plunger actuated electrical switches of the type which include a hollow body member having a spring influenced plunger which is slidable lengthwise therein and is adapted at its outer end to be engaged by an associated displaceable operating member such for example, as the pivoted brake pedal on a motor vehicle said plunger being adapted to open and close a pair of associated electrical terminals or contacts so that the switch may automatically illuminate a warning light at the rear of the vehicle when the brake pedal is depressed by the driver.

Although the improved switch is particularly suitable for the purpose mentioned it is to be understood that its use is not limited thereto but that it may be readily adapted for a variety of other purposes in similar low voltage electrical circuits.

It is well known that the operative position of the switch plunger in relation to the brake pedal or other actuating member must be accurately determined and in some cases adjusted during maintenance. Hitherto, the switch body has been almost invariably, made of metal and secured in the desired operative position by means of adjustable lock nuts.

The primary object of the present invention is to provide an improved low voltage electrical switch of the kind indicated which is capable of being quickly and easily secured in the desired operative position for example, in an apertured bracket or other support without the use of lock nuts. Furthermore, the operative position of the switch body and its associated plunger in relation to a brake pedal or the like may be quickly and easily adjusted if and when necessary.

The improved switch incorporates a minimum number of parts which may be easily assembled, mounted in the desired operative position and connected to associated electrical contacts without the use of special tools. In addition, the relatively movable parts of the switch are freely slidable and do not require the use of separate insulation to electrically insulate the switch from its apertured supporting bracket or other member.

According to the present invention the improved plunger actuated switch comprises a hollow body member having an open ended longitudinal passage therethrough, a spring influenced plunger slidably accommodated in said passage, adjustable retaining means for securing the assembly to an apertured fixed support, said body member and plunger being composed of resilient electrical non conductive material and a pair of electrical terminals one of which is detachably connected to said body member and the other to said plunger, said terminals being adapted for connection to electrical conductors and also to be moved into and out of engagement as a result of longitudinal movement of said spring influenced plunger so as to function as a switch.

Referring to the accompanying drawings:

FIGURE 1 is a part sectional elevation of a switch assembly in accordance with the present invention.

FIGURE 2 is a cross section on a reduced scale of the switch body member seen in FIGURE 1 but which has been turned at approximately right angles for convenience of illustration.

FIGURE 3 is a fragmentary front view of part of an apertured bracket or other fixed support for the switch assembly.

FIGURES 4 and 5 are a front view and a side view respectively of an electrical contact which is particularly suitable for detachable connection to the switch body member.

FIGURES 6 and 7 are a front view and a sectional elevation respectively of another electrical contact which is particularly adapted for fitting to a slidable plunger which forms part of the switch assembly.

In accordance with the member 2 and the plunger 3 are composed of resilient, electrical non-conductive material such for example, as nylon or any other suitable plastic. The body member has an axial hole 4 therethrough to slidably accommodate the plunger and is provided with adjustable retaining means for securing the assembly in the desired operative position on a fixed support such as an apertured wall, panel or bracket 6 on a motor vehicle adjacent to the hinged brake pedal thereof.

Said retaining means include a plurality of circumferentially spaced ribs 7 on the exterior of the body member and which extends lengthwise thereof. For example, three of such ribs may be employed and be spaced equidistantly on the body portion.

The outer surface of these ribs are serrated as at 8 so as to engage a complementary shaped edge portion 9 on the fixed bracket or other support and which defines the aperture therein through which the switch body may be passed. These serrations are longitudinally spaced on the aforesaid ribs and are preferably of substantially shape in cross section. The serrations on the several ribs are of substantially parallel, part circular form and coaligned in planes at substantially right angles to the axis of the body member.

In order to provide for insertion of the switch body into the aperture in its supporting member, the aperture boundary merges into a series of circumferentially spaced recesses 11 complementary to the shape and spacing of' the ribs on the switch body.

One of these ribs 7a is displaceable inwardly in relation to the switch body and for this purpose, it is partially separated from the switch body by an open ended gap 12 which is preferably of arcuate formation and located between the displaceable rib and the wall defining the open ended passage through the switch body, the gap extending lengthwise of the switch body and being closed at its inner side edge and open at its outer side edge as at 13 so as to separate the outer edge portion of the displaceable rib from the switch body. The opposite edge portion is thus connected to the switch body by a relatively thin web 14 which serves as a flexible hinge.

The free edge portion of the displaceable rib is provided with a laterally projecting bead or the like 16 which extends lengthwise of the displaceable rib and is adapted to detachably engage a complementary shaped recess 17 in the edge portion of the fixed supporting member defining the aperture therein. In order to facilitate engagement of this bead with its recess the adjacent recess for the displaceable rib is bounded at one side by a curved or inclined shoulder 18 adapted to be slidably engaged by the bead 16 upon turning movement of the switch body within the aperture in its fixed support so as to flex the displaceable rib 7a inwardly and finally enable the bead to engage its recess whereupon undesirable rotation of the switch assembly is opposed when in use.

In order to facilitate relative turning movement during installation and removal, of the switch body, it is preferably provided with one or more flat surfaces 19 which may be of hexagonal or any'other suitable form for engagement by a spanner.

present invention, both the body be provided with The inner end portion 21 of the switch body ispreferably of reduced diameter so as to render it more flexible and to facilitate its engagement with an electrical terminal or contact member 22 it is preferably provided with one or more longitudinal open mouthed slots so that the inner end portion of the switch body may be compressed so as to pass through an aperture 24 in the electrical contact which may be of apertured dished formation as seen more clearly in FIGS. 4 and 5.

To facilitate such engagement with its contact, the inner end of the switch body may be provided with an enlarged head 26 of substantially truncated conical formation which is slotted lengthwise and merges into an associated recess 27 of part circular formation at the rear thereof.

The aforesaid plunger 3 is preferably of substantially cylindrical, solid formation and provided at its outer end with an enlarged head piece 28 of any suitable form adapted to be engaged for example, by the brake pedal. The inner end portion 29 of the plunger is also preferably of reduced diameter and provided with an open mouthed longitudinal slot 31 so as to provide a pair of opposed spring legs 32. The end portions of these legs are also preferably provided with an enlarged head piece 33 of substantially truncated conical formation merging into a part circular recess 34 at the rear thereof adapted to accommodate another electrical terminal or contact 36 which may be of apertured plate like formation and one or more lugs 37 adapted to overhang the inner end of the switch body member and engage a flange 38 or the like on the electrical contact 22 thereon.

As seen more clearly in FIGURES 4 to 7 both the terminal 22 and its associated terminal 36 'are each provided with laterally extending ears or the like 39, 40 of substantially U-shape formation in cross section so that they may be readily connected to a flexible conductor by an appropriate crimping operation or in any other suitable manner.

The plunger is spring influenced so as to normally bring the contacts into engagement. For this purpose a helical spring 41 may encircle the inner portion of the plunger between longitudinally spaced and opposed shoulders 42, 43 on the plunger and the-inner end portion of the switch body.

The diameter of the enlarged headpiece 28 on the inner end portion of the plunger is preferably greater than the diameter of the entrance to the open ended passage 4 through the body portion or" the switch so as to oppose undesirable disconnection of the body portion, plunger and associated spring after these parts have been operatively assembled.

It will be appreciated that when in u-se, the assembled switch may be quickly [and easily mounted in the desired operative position on its fixed supporting member 6 simply by passing the switch body through the aperture therein with its ribs 7 in registry with the recesses 11 whereupon relative turning movement of the switch body has the effect of automatically moving the displaceable rib 7a inwardly until the retaining bead 16 thereon snaps into engagement with its recess 17 in the fixed supporting member and with the desired serrations 8 in engagement with the edge portion of the supporting member defining the aperture therein.

The switch assembly may be readily released simply by pressing the displaceable rib 7a inwardly so as to free the retaining bead from its recess and thus enable the body portion to be turned so as to permit relocation of the switch in relation to its fixed support, in accordance with requirements.

Another important advantage of the invention is that it enables the assembled body member and plunger to be quickly and easily connected to and disconnected from the associated electrical contacts 22, 36 when so desired without the use of special tools. For example, the wiring secured to the inner end portions of the harness may be fitted with the electrical contacts mentioned adjacent to the fixed supporting bracket 6. The assembled member 2, plunger'3 and spring 41 form a unit which may be quickly and easily secured to the supporting bracket as aforesaid in the desired operative position in relation to the brake pedal of the motor vehicle whereupon the electrical contacts may be readily plunger and the body member respectively simply by pushing the apertured portions of the contacts over the resilient end portions of the plunger and body member until they finally snap into engagement with the respective recesses 27, 34 therein;

Various alterations, modifications and/ or additions may be introduced into the foregoing construction and arrangement of parts without departing from the ambit of the invention as defined by the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A plunger actuated electrical switch of the kind indicated characterized in that both the body member and its associated spring influenced plunger are composed of resilient electrical non-conductive material, the body member having an open ended axial hole therethrough to slidably accommodate the plunger and being provided With adjustable retaining means for securing the assembly to an apertured fixed support, said retaining means including a plurality of circumferentially spaced ribs on 'the exterior of said body member and which extend lengthwise thereof, the aperture in said fixed support being of complementary formation so that the ribbed body member may be. inserted into said aperture and turned in relation thereto so as to move said ribs out of registry with circumferentially spaced gaps forming part of said aperture and means for opposing relative turning movement between said body member and the apertured fixed support after. the former has been located in the desired operative position, said means for opposing relative turning movement including one of said ribs which is displaceable inwardly in relation to said body member in that it is partially separated from said body member by an open ended gap located between the displaceable rib and a wall defining the open ended passage through said body member, said g'ap extending lengthwise of the body member and being open at its outer side edge. and closed at its opposite inner side edge where the adjacent portion of said displaceable rib is connected to the body portion by a web which serves as a flexible hinge, the free edge portion of the displaceable rib being provided with a laterally projecting bead which extends lengthwise thereof and is adapted to detacha bly engage a complementary shaped recess in the edge portion of said fixed supporting member defining the aperture therein.

2. -A plunger actuated electrical switch of the kind indicated characterised in that both the body member and its associated spring influenced plunger are composed of resilient electrical nonconductive material, the body memher having an open ended axial hole therethrough to slidably accommodate the plunger and being provided with adjustable retaining means for securing the assembly to an apertured fixed support, said retaining means including a plurality of circumferentially spaced ribs on the exterior of said body member and which extend lengthwise thereof, the aperture in said fixed support being of complementary formation so that the ribbed body member may :be inserted into said aperture and turned in relation thereto so as to move said ribs out of registry with circumferentially spaced gaps forming part of said aperture and means for opposing relative turning movement between said body member and the apertured fixed support after the former has been located in the desired operative position, the outer surfaceof each of said ribs being serrated in such a manner that the serrations on the several ribs are substantially parallel, of part circular form and coaligned in planes at substantially right angles to the axis of said body member, the serrations being adapted to engage a complementary shaped edge portion on that part of the fixed support which defines the aperture therein, said means for opposing relative turning movement including one of said ribs which is displaceable inwardly in relation to said body member in that it is partially separated from said body member by an open ended gap located between the displaceable rib and a wall defining the open ended passage through said body member, said gap extending lengthwise of the body member and being open at its outer side edge and closed at its opposite or inner side edge where the adjacent portion of said displaceable rib is connected to the body portion by a web which serves as a flexible hinge, the free edge portion of the displaceable rib being provided with a laterally projecting bead which extends lengthwise thereof and is adapted to de- 6 tacha'bly engage a complementary shaped recess in the edge portion of said fixed supporting member defining the aperture therein.

References Cited by the Examiner UNITED STATES PATENTS ROBERT K. SCHAEFER, Primary Examiner. H. HOHAUSER, Assistant Examiner. 

1. A PLUNGER ACTUATED ELECTRICAL SWITCH OF THE KIND INDICATED CHARACTERIZED IN THAT BOTH THE BODY MEMBER AND ITS ASSOCIATED SPRING INFLUENCED PLUNGER ARE COMPOSED OF RESILIENT ELECTRICAL NON-CONDUCTIVE MATERIAL, THE BODY MEMBER HAVING AN OPEN ENDED AXIAL HOLE THERETHROUGH TO SLIDABLY ACCOMMODATE THE PLUNGER AND BEING PROVIDED WITH ADJUSTABLE RETAINING MEANS FOR SECURING THE ASSEMBLY TO AN APERTURED FIXED SUPPORT, SAID RETAINING MEANS INCLUDING A PLURALITY OF CIRCUMFERENTIALLY SPACED RIBS ON THE EXTERIOR OF SAID BODY MEMBER AND WHICH EXTEND LENGTHWISE THEREOF, THE APERTURE IN SAID FIXED SUPPORT BEING OF COMPLEMENTARY FORMATION SO THAT THE RIBBED BODY MEMBER MAY BE INSERTED INTO SAID APERTURE AND TURNED IN RELATION THERETO SO AS TO MOVE SAID RIBS OUT OF REGISTRY WITH CIRCUMFERENTIALLY SPACED GAPS FORMING PART OF SAID APERTURE AND MEANS FOR OPPOSING RELATIVE TURNING MOVEMENT BETWEEN SAID BODY MEMBER AND THE APERTURED FIXED SUPPORT AFTER THE FORMER HAS BEEN LOCATED IN THE DESIRED OPERATIVE POSITION, SAID MEANS FOR OPPOSING RELATIVE TURNING MOVEMENT INCLUDING ONE OF SAID RIBS WHICH IS DISPLACEABLE INWARDLY IN RELATION TO SAID BODY MEMBER IN THAT IT IS PARTIALLY SEPARATED FROM SAID BODY MEMBER BY AN OPEN ENDED GAP LOCATED BETWEEN THE DISPLACEABLE RIB AND A WALL DEFINING THE OPEN ENDED PASSAGE THROUGH SAID BODY MEMBER, SAID GAP EXTENDING LENGTHWISE OF THE BODY MEMBER AND BEING OPEN AT ITS OUTER SIDE EDGE AND CLOSED AT ITS OPPOSITE INNER SIDE EDGE WHERE THE ADJACENT PORTION OF SAID DISPLACEABLE RIB IS CONNECTED TO THE BODY PORTION BY A WEB WHICH SERVES AS A FLEXIBLE HINGE, THE FREE EDGE PORTION OF THE DISPLACEABLE RIB BEING PROVIDED WITH A LATERALLY PROJECTING BEAD WHICH EXTENDS LENGTHWISE THEREOF AND IS ADAPTED TO DETACHABLY ENGAGE A COMPLEMENTARY SHAPED RECESS IN THE EDGE PORTION OF SAID FIXED SUPPORTING MEMBER DEFINING THE APERTURE THEREIN. 